Networks provide communications from one node located on a network to other nodes located on the network. The nodes are typically personal computers, workstations, file or print servers, or any other suitable device and utilize the network to communicate information to other nodes on the network. For example, a workstation on a network may communicate with a server or a printer over the network. In a more basic network, a sensor may communicate information to a base computer which may communicate information to a mechanical actuator. The base computer may communicate with a variety of sensors and a mechanical actuator to perform a desired operation.
Those skilled in the art will appreciate that there are many different types of networks. For example, the network may be a Local Area Network (LAN). The nodes on the LAN may communicate with other LANs via, for example, a Wide Area Network (WAN). To provide routing of the data within a network and to various other connected networks, the network may use equipment to facilitate routing of data. For example, switches, routers, hubs, or bridges may be used to transmit and communicate data between nodes and networks.
The network may use one or more protocols to allow the nodes to receive and transmit data. One of the most commonly used protocols is Ethernet. Ethernet allows nodes to package and transmit data to a desired node, and, once received, unpackage the data at the desired node.
A process control network (PCN) is a communications network that is used to transmit instructions and data between control and measurement nodes and equipment. Ethernet switches are part of a process control network and act as conduits to transfer packets of data within process control network nodes. Ethernet switches logically partition these packets to travel directly between their source and their destination.
Each node on a network has a unique network address called a data link control (DLC) address or media access control (MAC) address. Sending the packets directly to the desired media access control address increases security as users at varying nodes are less apt to access other users' data. By sending the packets directly to the desired location and reducing the number of packets on other segments, the overall performance and efficiency are improved. Process control networks place a high emphasis on expedient and deterministic throughput of data, while minimizing internal and external interference. Details of process control networks are disclosed in, for example, ANSI/ISA -95.00.01-2000 Enterprise-Control System Integration Part 1: Models, (ANSI/ISA 2000) and ANSI/ISA-95.00.02-2001 Enterprise-Control System Integration Part 2: Object Model Attributes: Object Model Attributes, (ANSI/ISA 2001), as well as, A Reference Model for Computer Integrated Manufacturing (CIM) (Theodore J. Williams et al., 2d ed., Instrument Society of America 1989).
Accordingly, an efficient and effective system and method are needed for ensuring that the process control network is not interfered with by internal or external elements, preventing timely flow of critical data. In addition, systems and methods are needed to increase the overall efficiency of a network by reducing the volume of non-critical data through the network or halting the flow of this non-critical data until a better suited time.